In a belt conveyor the belt rotates between two end rollers, at least one of which is a drive roller. A drive motor can be arranged inside the drive roller. The conveyor transfer loose material from the feed end to the discharge end. The discharge ends of large belt conveyors having a belt width of over 650 mm are commonly protected with protective covers, since the material being transported does not emit dust on the belt, but when it leaves the belt, dust is released. The protective cover also protects the components of the discharge end against the impacts of weather and muffles noise. The discharge end can be provided with channels that suck dust.
In the presently used technique, the protective covers of large conveyors are made of steel and are fixed with bolts to the frame of the discharge end or the frame of the conveyor and they usually have inspection lids for monitoring the condition of the drive roller of the conveyor, the motor of the drive roller and other components of the discharge end of the conveyor. The inspection lids have been used for allowing the handling of the lids by one service-man and for eliminating the need to remove a large and heavy protective cover.
Usually the inspection lids are located on the protective cover and/or at the sides thereof and they can be opened or transparent. The lids are fairly small and they only allow viewing the equipment and thus checking and discovering the condition. The lids have not allowed any maintenance actions. In view of the regulation of the material guide plate of a belt conveyor, maintenance of the drive drum, condition monitoring of the cleaners and clearing of hopper clogging, the present protective cover constructions that are fixed with bolts and provided with only fairly small inspection lids are highly unpractical and expensive solutions.
In the prior art solutions the inspection lid in the protective cover only allows checking the discharge end. Further, the lids provide poor visibility so that it is impossible to see properly through them, and thus it impossible even to reliably check the situation. Also, maintenance is troublesome in the prior art solutions due to poor accessibility of the discharge end of the conveyor. In the prior art solutions the protective cover of the discharge end of the conveyor has to be removed totally for maintenance purposes. The protective cover is, however, of fairly big size and heavy and the opening requires a number of workers and, for assistance, lifting tackles and at least one crane. Only to open the protective cover takes from half an hour even up to half of a day.
In the prior art solutions, maintenance is often neglected due to its difficulty. When maintenance is neglected, material to be transferred is allowed to accumulate under the return belt, which causes clogging. Clogging generates disturbances in the process, which may result in production breaks. Further, when material streams change, the guide plate should be adjusted for ensuring optimal performance, but the adjustment is troublesome and therefore it may often be neglected.
At the worst case, using prior art technology, the maintenance operations for a discharge end of a belt conveyor can be neglected due to the difficulty and time-consuming character, which may even result in break down of the equipment. This, in turn, causes repair costs or even replacement of the discharge end of the conveyor as a whole, which is expensive already due to equipment costs and additionally causes an even longer break in production.